GB734796A - A combined die-pressing and extrusion process and apparatus for the production of hollow bodies having protuberances on their outer face and one or more extensions at one end - Google Patents

Abstract

734,796. Extruding; forging. KREIDLER, A. Dec. 23, 1952 [Dec. 27, 1951], No. 32583/52. Class 83 (4). A combined die-pressing and extrusion process for producing hollow bodies with exterior protuberances on their side faces and one or more extensions at one end comprises inserting a billet in a die whose side walls are shaped to form the side faces and protuberances, and pressing the billet by an extrusion ram so as to first fill the die and then by continued pressure to displace the material of the inner portion of the billet through one or more extrusion orifices at one end of the die to form th extension or extensions, the outer portion of the billet remaining around the ram as the-wall of the hollow body. The extension or extensions may be hollow or solid. A hollow article of light metal is made by first upsetting a tubular billet in a two-part die 6<SP>1</SP>, 6<SP>11</SP>, by means of a punch 8 to form an enlarged head 1 with projections 2 and an annular flange 3, the die orifice 7 being then closed by a tubular plunger 12, Fig. 4 (not shown) which co-operates with the mandrel 10. The tubular plunger is then retracted and the inner portion of the billet is extruded between the die orifice 7 and the mandrel 10 to form a tubular shank 4. The mandrel 10 may be operated independently of the punch 8 or be attached thereto. The billet may be heated. The lower surface, of the punch has a skirt for forming an upstanding internal flange. In another embodiment a shorter billet is used and the upper part of the head is formed by backward extrusion.